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Magnetic field-induced momentum-dependent symmetry breaking in a kagome superconductor

Nature Physics (2026)Cite this article

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Abstract

When several degrees of freedom in quantum materials have similar energy scales, the intertwined electronic orders, which exhibit broken symmetries, are often strongly coupled. Recent studies on kagome superconductors, such as CsV3Sb5, report rotational and time-reversal symmetry breaking linked to a charge density wave. Here we observe a momentum-selective response of the electronic structure of CsV3Sb5 to an external magnetic field. By performing angle-resolved photoemission spectroscopy in a tunable magnetic field, we demonstrate that the response of the electronic structure is compatible with piezomagnetism along with strong orbital selectivity. Our results show that the origin of the time-reversal symmetry breaking is associated with the vanadium Van Hove singularities at the onset of the charge-density-wave order. We also demonstrate the presence of fluctuations beyond the charge ordering temperature. Our results reveal that magnetic fields can be used as tuning knobs for disentangling intertwined orders in the momentum space for quantum materials.

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Fig. 1: Magneto-ARPES experimental set-up and the measured electronic structure of CsV3Sb5.
Fig. 2: Field response of the electronic states originating from the V d orbitals near K and K’.
Fig. 3: Magnetic field dependence of the electronic spectrum near K.
Fig. 4: Field response of the electronic states originating from the Sb p orbitals near Γ.

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Data availability

All data needed to evaluate the conclusions are available from the corresponding authors upon reasonable request. Source data are provided with this paper.

Code availability

The band structure calculations used in this study are available from the corresponding authors upon reasonable request.

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Acknowledgements

The ARPES work at Rice University was supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative (Grant No. GBMF9470 to M.Y.), the Robert A. Welch Foundation (Grant No. C-2175 to M.Y.) and the US Department of Energy, Basic Energy Sciences (Grant Nos. DE-SC0021421 to M.Y. and DE-SC0026179). The single-crystal synthesis work at UW was supported by the Air Force Office of Scientific Research (Award No. FA2386-21-1-4060 to J.-H.C.) and the David Lucile Packard Foundation (J.-H.C.). R.M.F. was supported by the Air Force Office of Scientific Research (Award No. FA9550-21-1-0423). Z.W. is supported by the US Department of Energy, Basic Energy Sciences (Grant No. DE-FG02-99ER45747). B.Y. acknowledges financial support from the Israel Science Foundation (Grant No. 2974/23) and the National Science Foundation through the Penn State Materials Research Science and Engineering Center (Grant No. DMR 2011839). Efforts to grow single crystals at Rice are supported by the US Department of Energy, Basic Energy Sciences (Grant No. DE-SC0026179 to P.D.). Part of the materials characterization efforts at Rice is supported by the Robert A. Welch Foundation (Grant No. C-1839 to P.D.). J.K. acknowledges support from the Robert A. Welch Foundation (Grant No. C-1509) and the Gordon and Betty Moore Foundation (Grant No. 11520). J.M. and A.P. thank the project Quantum Materials for Applications in Sustainable Technologies (QM4ST), funded as Project No. CZ.02.01.01/00/22_008/0004572 by Programme Johannes Amos Comenius, through the Excellent Research call. Y.H. is supported by the Air Force Office of Scientific Research (Award No. FA9550-24-1-0048).

Author information

Author notes

  1. These authors contributed equally: Jianwei Huang, Zheng Ren.

Authors and Affiliations

  1. Department of Physics and Astronomy, Rice University, Houston, TX, USA

    Jianwei Huang, Zheng Ren, Jounghoon Hyun, Yichen Zhang, Thomas A. Hulse, Yaofeng Xie, Ziqin Yue, Junichiro Kono, Pengcheng Dai & Ming Yi

  2. Smalley-Curl Institute, Rice University, Houston, TX, USA

    Jianwei Huang, Zheng Ren, Jounghoon Hyun, Yichen Zhang, Thomas A. Hulse, Yaofeng Xie, Ziqin Yue, Junichiro Kono, Pengcheng Dai & Ming Yi

  3. Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel

    Hengxin Tan & Binghai Yan

  4. Applied Physics Graduate Program, Smalley-Curl Institute, Rice University, Houston, TX, USA

    Thomas A. Hulse & Ziqin Yue

  5. Department of Physics, University of Washington, Seattle, WA, USA

    Zhaoyu Liu, Jonathan M. DeStefano & Jiun-Haw Chu

  6. Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA

    Junichiro Kono

  7. Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA

    Junichiro Kono

  8. Rice Laboratory for Emergent Magnetic Materials, Rice University, Houston, TX, USA

    Pengcheng Dai & Ming Yi

  9. Department of Applied Physics, Yale University, New Haven, CT, USA

    Yu He

  10. New Technologies - Research Centre, University of West Bohemia in Pilsen, Plzeň, Czech Republic

    Aki Pulkkinen & Ján Minár

  11. Department of Physics, Boston College, Chestnut Hill, MA, USA

    Ziqiang Wang

  12. Department of Physics, The Pennsylvania State University, University Park, PA, USA

    Binghai Yan

  13. Department of Physics, The Grainger College of Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Rafael M. Fernandes

  14. Anthony J. Leggett Institute for Condensed Matter Theory, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Rafael M. Fernandes

Authors
  1. Jianwei Huang
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  2. Zheng Ren
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  3. Hengxin Tan
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  20. Ming Yi
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Contributions

M.Y. and J. Huang proposed and designed the project. Z.L. grew the CsV3Sb5 single crystals with the help of J.M.D. under the guidance of J.-H.C. J. Huang, Z.R., J. Hyun, T.A.H. and Z.Y. carried out the ARPES measurements under the guidance of M.Y., Y.H. and J.K. J. Huang performed the magneto-ARPES data analysis. Y.X., Z.L. and J.M.D. grew single crystals for control measurements under the guidance of P.D. and J.-H.C. H.T., B.Y. and Z.W. conducted the first-principles calculations. Y.Z. carried out the ab initio one-step model ARPES calculations with advice from A.P. and J.M. Y.Z. analysed the one-step calculated data. R.M.F. performed the phenomenological theoretical analysis. J. Huang and M.Y. wrote the paper with input from all co-authors.

Corresponding authors

Correspondence to Jianwei Huang or Ming Yi.

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Extended data

Extended Data Fig. 1 Electronic response of CsV3Sb5 around the K point under a magnetic field.

(a)-(c) Constant energy contours at -0.35 eV without a magnetic field, with +1.6 mT, and with -1.6 mT, respectively. (d)-(e) The corresponding spectral images along cut1 indicated in (a). (g) The spectral image obtained by subtracting (e) from (f). (h)-(k) Same as (d)-(g) but along cut2 indicated in (a).

Extended Data Fig. 2 Momentum-selective spectral broadening in CsV3Sb5 under a magnetic field.

(a)-(c) Constant energy contours at -0.35 eV without a magnetic field, with +1.6 mT, and with -1.6 mT, respectively. The yellow arrows point to the Fermi surface sheets that broaden substantially under the corresponding magnetic field. (d)-(f) Spectral images taken along cut1 and cut2 indicated in (a), with cut directions perpendicular to the Fermi surface sheets. Selective momentum broadening of the α and β bands is evident from both the Fermi surface sheets and the corresponding band spectral images.

Extended Data Fig. 3 Simulation of the magneto-dichroic effect of the ARPES spectra.

(a) Simulated spectral images to reproduce the ARPES observations based on the band structure obtained by DFT calculations (black dashed line in (c)). The DFT band dispersions were extracted along the momentum path along cut1 in Fig. 2b of the main text. Distinct imaginary parts of the self-energies were applied to the left and right momentum regions in each panel to simulate the momentum-selective spectral broadening under a magnetic field. (b) Simulated magneto-dichroic spectral image by subtracting the left panel from the right panel in (a). (c) Measured magneto-dichroic spectral image from Fig. 2h in main text. (d)-(f) Same as (a)-(c) but simulating the magneto-dichroic spectral image along cut2 in Fig. 2b of the main text.

Extended Data Fig. 4 Constant energy contour mappings showing the two opposite K regions.

Constant energy contours at -0.2 eV consist of three separate DA30 deflector mode mappings on the same sample, showing the two opposite K regions using a helium lamp light source. The mappings were taken at magnetic fields of -2.1 mT, 0 mT, and 2.1 mT. The green arrows point to the Fermi surface sheets respond most prominently to the magnetic field. The two Fermi surface sheets around the two opposite K regions exhibit the same behavior, which is also evident by our observations in Fig. 2c,d of the main text considering the crystalline translational symmetry.

Extended Data Fig. 5 One-step model ARPES calculations of CsV3Sb5 under external magnetic fields within the atomic-sphere approximation.

(a) Constant energy contour under zero field calculated at E - EF = -0.26 eV using experimental geometry and inputs. Photon incidence direction and the s and p polarizations of photons are illustrated by the hν/c and the symbols on the top left. (b) ARPES spectra of Cut 1 spanned by the vertical cyan line in (a), similar to experiments performed in main text Fig. 2(e). The momentum distribution curve (MDC) taken at E - EF = -0.2 eV is shown on top. A Fermi-Dirac distribution function of 20 K convolved with a putative 20 meV experimental resolution is applied to the calculated data. (c, d) Same as (b), but under external magnetic fields of +117.5 and -117.5 T, respectively. (e - g) Spin integrated MDCs reproduced from (b-d) and their spin-resolved components projected along z under 0, +117.5, and -117.5 T, respectively. (h) Spin-integrated MDCs taken at E - EF = -0.2 eV of Cut 1 but at low fields of 0, +2.35, and -2.35 T.

Source data

Extended Data Fig. 6 Fermi surface of the nearest-neighbor kagome model of Methods Section F in the absence of a magnetic field.

The parameters are set as t = 1 and μ = -0.08. Bz = 0 to focus on the effect of Φ1, which is varied as indicated in each panel (Φ1 = 0, 0.01, and 0.2). As expected, the Fermi surface distortion is negligible for small Φ1.

Source data

Extended Data Fig. 7 Fermi surface of the nearest-neighbor kagome model of Methods Section F in the presence of a magnetic field.

(a) Fermi surface for t = 1, μ = -0.08, Φ1 = 0 and Bz = 0. The horizontal mirror plane is preserved. (b) Fermi surface with t = 1 and μ = -0.08, but now with Φ1 = 0.01 and a positive field Φ2Bz = 0.1. (c) Same as (b) but with a negative field Φ2Bz = -0.1. In both (b) and (c), the horizontal mirror symmetry and the C6 symmetries are broken, consistent with the symmetry-breaking behavior observed in the ARPES data from the perspective of the spectral weight distribution.

Source data

Extended Data Fig. 8 Γ-pocket Fermi surface fitting based on the model of Methods Section F, Eq. (7).

(a) Fermi pocket diameter as a function of the azimuthal angle obtained by fitting the radial MDCs without and with a magnetic field. The curves at -1.6 mT and 1.6 mT are offset for clarity with the reference lines shown for each. Error bars represent the standard deviation of the Lorentzian fits to the corresponding MDC peaks along different Fermi surface directions with 95% confidence interval. (b) Square of the Fermi momentum for -1.6 mT normalized by the zero field value overlaid with the fitting results using Eq. 7. Error bars are derived from the corresponding error bars in (a). (c) Fermi pocket diameter for -1.6 mT and 1.6 mT normalized by its zero-field value measured at 35 K. Error bars are derived from the corresponding error bars in (a). All curves are fitted with the function A + B \(\cos\)(2(θ + π)). The red and blue dashed lines indicate the deviation of the long axes of the elliptical Fermi pockets away from the K point at -1.6 mT (6.9∘) and 1.6 mT (2.3∘), respectively.

Source data

Supplementary information

Supplementary Information (download PDF )

Supplementary Notes I-VI and Figs. 1–9.

Source data

Source Data Fig. 2 (download XLSX )

Source data for the momentum distribution curves at different temperatures and the fitting results.

Source Data Fig. 3 (download XLSX )

Source data for the momentum distribution curves under different magnetic fields and the fitting results.

Source Data Fig. 4 (download XLSX )

Source data for the momentum distributions curves and the extracted Fermi surface diameters along different in-plane azimuthal directions, the extracted spectral width difference between K and K’ and the Fermi surface anisotropic ratio as a function of temperature.

Source Data Extended Data Fig. 5 (download XLSX )

Source data for the spin-integrated and spin-resolved momentum distribution curves under different magnetic fields from theoretical calculations.

Source Data Extended Data Fig. 6 (download XLSX )

Source data for the spectral weight distribution of the Fermi surface obtained by the phenomenological model in the absence of a magnetic field.

Source Data Extended Data Fig. 7 (download XLSX )

Source data for the spectral weight distribution of the Fermi surface obtained by the phenomenological model in the presence of a magnetic field.

Source Data Extended Data Fig. 8 (download XLSX )

Source data for the extracted Fermi surface diameter and square of the Fermi momentum along different in-plane azimuthal directions.

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Huang, J., Ren, Z., Tan, H. et al. Magnetic field-induced momentum-dependent symmetry breaking in a kagome superconductor. Nat. Phys. (2026). https://doi.org/10.1038/s41567-026-03205-7

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